Various types of seat belt systems have been used to secure occupants in their seats in aircraft and other vehicles. Commercial aircraft, for example, typically use 2-point restraint systems (e.g., lap seat belts) to secure occupants in their seats. Airbag systems have also been used to protect passengers from strike hazards in automobiles, aircraft, and other vehicles. In automobiles, for example, airbags can be stowed in the steering column, dashboard, side panel, or other location. In the event of a collision or other dynamic event of sufficient magnitude, a sensor detects the event and transmits a corresponding signal to an initiation device (e.g., a pyrotechnic device) on an airbag inflator. This causes the inflator to release compressed gas into the airbag, rapidly inflating the airbag and deploying it in front of the driver or other occupant to protect them from impact injuries.
As noted above, commercial aircraft typically use lap seat belts to secure occupants in their seats. Conventional lap seat belts, however, do not stop the occupant's upper torso from rotating forward in a crash or other rapid deceleration event. If the occupant is seated behind another seat or a forward monument when this happens, the occupant's head may strike the forward structure. Although shoulder belts or other multi-point systems with shoulder harnesses can reduce forward head movement, substantial head movement may still occur. To address this, an airbag can be deployed in front of the occupant so that the occupant's head contacts the airbag as it rotates forward instead of the forward structure. Although the use of airbags can significantly reduce the likelihood of head or neck injury, it can be important to ensure that the occupant contacts the airbag in such a way that it does not put undue stress on the occupant's neck, head or other portion of the occupant's body. If an airbag is not present and the occupant is seated behind a monument, then it can also be important to ensure that the occupant contacts the monument in a similar way.